For anyone who uses Facebook, you will be familiar with the feature called “Your Memories on this Day.” Unbidden, this monstrous digital storehouse will send you a notice containing old posts and photos you have shared with your friends on the same date in previous years. On a recent day, it reminded me of the following entry I had posted:

That bittersweet moment when you realize that somewhere along the way “Mommy” has changed to “Mom.”

My friends responded with different comments, including one mother who commented that her kids still called her “Mommy” when they want something. Another friend with a younger child than mine sent the already wistful remark that she dreaded this inevitable change. Different reactions, but both recognized the same thing – that life moves forward, change is inevitable, and relationships evolve.

Any new parent knows that watching their child achieve those early developmental milestones is miraculous: first real smile, first solid food, first tooth, first step, first intentional word (hopefully “Mama”!). They are religiously recorded and shared with family and friends – these days likely on Facebook or other social media. Early achievement of these signposts brings pride, while slowness in getting there provokes anxiety and possible trips to the family doctor.

The first firsts are the most exciting and wonderous of all, so first children typically get the most attention for their accomplishments. It’s just that little bit less miraculous the second or third time around – been there, done that! The truth is subsequent children simply get shorter shrift. In my house, there were noticeably more baby photos and film of me than my younger sister. My parents always insisted that the camera had broken around the time of her birth. I expect this was true, but my sister still nurses lingering resentment over this. For my part, I wonder if the camera would have been replaced more quickly if it had broken following my birth. Then again, two children are more expensive than one so perhaps there was a financial basis for the problem. But you see the point.

Later on in life the firsts change from those tracked by your parents to the ones you track yourself: first job, first car, first boyfriend or girlfriend, first apartment. And eventually, many of us become parents and start tracking the firsts of our children: first day of school, first badge or winning ribbon, first time letting the kid take the car out alone (gulp!).

But for every first, there often comes a last. Some of these can bring joy, such as last payment to the orthodontist. Some of them are remarkable, such as your “baby” graduating from high school or university. But many are less obvious and remarked upon: for example, when exactly did your child lose his last tooth and the Tooth Fairy make her last visit? When did your child last hold your hand in public or climb into your bed at night? When did your kids stop calling you “Mommy?”

And this continues throughout life. The decline of independence in older age adults can at first be imperceptible. But at some point you realize your parents have aged. When was the last time your father could walk without a cane? When was the last time your mother could change the TV channel or make a phone call unassisted? When was the last time Grandma and Grandpa were able to really get on the floor to play with or chase around their grandkids? And there are the big lasts as well – the last time your parents drove the car, the last time they took a trip together on their own, the last time they remembered your birthday unprompted. When did the “new normal” cease to be “new” and become just “normal”?

So go ahead, enjoy and record those remarkable firsts. But don’t forget to pay attention to the importance of the lasts either, for they are just as telling.